t/gui: Add imgui code

src/xrt/targets/gui/CMakeLists.txt

@@ -15,6 +15,8 @@ include_directories(
 
 set(SOURCE_FILES
 	gui_common.h
+	gui_imgui.c
+	gui_imgui.h
 	gui_main.c
 	gui_ogl.c
 	gui_prober.c
@@ -22,6 +24,22 @@ set(SOURCE_FILES
 	gui_sdl2.c
 	../../../external/glad/gl.h
 	../../../external/glad/gl.c
+	../../../external/imgui/cimgui.cpp
+	../../../external/imgui/cimgui.h
+	../../../external/imgui/imconfig.h
+	../../../external/imgui/imgui.cpp
+	../../../external/imgui/imgui.h
+	../../../external/imgui/imgui_demo.cpp
+	../../../external/imgui/imgui_draw.cpp
+	../../../external/imgui/imgui_impl_opengl3.cpp
+	../../../external/imgui/imgui_impl_opengl3.h
+	../../../external/imgui/imgui_impl_sdl.cpp
+	../../../external/imgui/imgui_impl_sdl.h
+	../../../external/imgui/imgui_internal.h
+	../../../external/imgui/imgui_widgets.cpp
+	../../../external/imgui/imstb_rectpack.h
+	../../../external/imgui/imstb_textedit.h
+	../../../external/imgui/imstb_truetype.h
 	)
 
 add_executable(gui

src/xrt/targets/gui/gui_common.h

@@ -94,6 +94,14 @@ struct gui_ogl_texture
 int
 gui_sdl2_init(struct program *p);
 
+/*!
+ * Loop until user request quit and show Imgui interface.
+ *
+ * @ingroup gui
+ */
+void
+gui_imgui_loop(struct program *p);
+
 /*!
  * Loop until quit signal has been received.
  *

src/xrt/targets/gui/gui_imgui.c

@@ -0,0 +1,125 @@
+// Copyright 2019, Collabora, Ltd.
+// SPDX-License-Identifier: BSL-1.0
+/*!
+ * @file
+ * @brief  Main entrypoint for the Monado GUI program.
+ * @author Jakob Bornecrantz <jakob@collabora.com>
+ * @ingroup gui
+ */
+
+#include "util/u_var.h"
+#include "util/u_time.h"
+#include "util/u_misc.h"
+#include "util/u_sink.h"
+#include "util/u_format.h"
+
+#include "xrt/xrt_prober.h"
+
+#include "gui_common.h"
+#include "gui_imgui.h"
+
+
+/*
+ *
+ * Structs and defines.
+ *
+ */
+
+/*!
+ * Internal gui state.
+ *
+ * @ingroup gui
+ */
+struct gui_imgui
+{
+	bool show_demo_window;
+	struct xrt_colour_rgb_f32 clear;
+};
+
+
+/*
+ *
+ * 'Exported' functions.
+ *
+ */
+
+void
+gui_imgui_loop(struct program *p)
+{
+	// Need to call this before any other Imgui call.
+	igCreateContext(NULL);
+
+	// Local state
+	ImGuiIO *io = igGetIO();
+
+	// Setup Platform/Renderer bindings
+	igImGui_ImplSDL2_InitForOpenGL(p->win, p->ctx);
+	igImGui_ImplOpenGL3_Init(NULL);
+
+	// Setup Dear ImGui style
+	igStyleColorsDark(NULL);
+
+	// Main loop
+	struct gui_imgui gui = {0};
+	gui.clear.r = 0.45f;
+	gui.clear.g = 0.55f;
+	gui.clear.b = 0.60f;
+	u_var_add_root(&gui, "GUI Control", false);
+	u_var_add_rgb_f32(&gui, &gui.clear, "Clear Colour");
+	u_var_add_bool(&gui, &gui.show_demo_window, "Demo Window");
+	u_var_add_bool(&gui, &p->stopped, "Exit");
+
+	while (!p->stopped) {
+		SDL_Event event;
+
+		while (SDL_PollEvent(&event)) {
+			igImGui_ImplSDL2_ProcessEvent(&event);
+
+			if (event.type == SDL_QUIT) {
+				p->stopped = true;
+			}
+
+			if (event.type == SDL_WINDOWEVENT &&
+			    event.window.event == SDL_WINDOWEVENT_CLOSE &&
+			    event.window.windowID == SDL_GetWindowID(p->win)) {
+				p->stopped = true;
+			}
+		}
+
+		// Start the Dear ImGui frame
+		igImGui_ImplOpenGL3_NewFrame();
+		igImGui_ImplSDL2_NewFrame(p->win);
+
+		// Start new frame.
+		igNewFrame();
+
+		// Render the scene into it.
+		gui_scene_manager_render(p);
+
+		// Handle this here.
+		if (gui.show_demo_window) {
+			igShowDemoWindow(&gui.show_demo_window);
+		}
+
+		// Build the DrawData (EndFrame).
+		igRender();
+
+		// Clear the background.
+		glViewport(0, 0, (int)io->DisplaySize.x,
+		           (int)io->DisplaySize.y);
+		glClearColor(gui.clear.r, gui.clear.g, gui.clear.b, 1.0f);
+		glClear(GL_COLOR_BUFFER_BIT);
+
+		igImGui_ImplOpenGL3_RenderDrawData(igGetDrawData());
+
+		SDL_GL_SwapWindow(p->win);
+
+		gui_prober_update(p);
+	}
+
+	// Cleanup
+	u_var_remove_root(&gui);
+	igImGui_ImplOpenGL3_Shutdown();
+	igImGui_ImplSDL2_Shutdown();
+	igDestroyContext(NULL);
+}

src/xrt/targets/gui/gui_imgui.h

@@ -0,0 +1,14 @@
+// Copyright 2019, Collabora, Ltd.
+// SPDX-License-Identifier: BSL-1.0
+/*!
+ * @file
+ * @brief  Imgui integration for gui.
+ * @author Jakob Bornecrantz <jakob@collabora.com>
+ * @ingroup gui
+ */
+
+#pragma once
+
+#define CIMGUI_DEFINE_ENUMS_AND_STRUCTS
+#include "imgui/cimgui.h"
+#include "glad/gl.h"